couple questions

i just bought a silvia K’s a week ago and was wondering a few things it’s got the black top in it and was wondering if i ran one bar boost would do damage or should i keep it to like 8or 9 lbs… also on pulls my boost gauge reads from .40 - .49 it is always different on every pull. i tested it while in second gear i dunno if i have a boost leak or if this is normal thanks

What mods are all done to it?

test your boost in 4th gear, should be more consistent.